Respironics Bipap Auto - questions re use

This week end have been doing some experimenting with machines & masks but in particular am trying to set up a new Respironics Bipap Auto.

The settings seem pretty simple but the results are not what I had expected am wondering what others have found.

My 1st test was to set it up in Bipap mode (to compare with a Bipap Pro 2) and that seems normal - very much the same to set up.

The part that doesn't seem as I expect is the Auto Bipap Mode (no BiFlex). I had imagined it would work like a Bipap with 2 pressures set as you wish, then the machine would adjust ipap & epap if it detects problems.

I put a CMS dial guage on the machine & set it for
epap min 10
ipap max 14
ps 3
risetime 2
Using a Resmed Activa Nasal Mask (the floating one).

Then turned it on & measured the CMS using the dial guage and compared this to the readout on the LCD panel on the machine.

What the Bipap Auto does is start off delivering the min epap and adjusts ipap to 2 CMS above this. So The readout on the machine showed 10 & 12 - when the dial guage was connected at the machine end of the hose, it also showed pressures of 10 & 12. But, when the dial guage is connected at the mask end it shows 9.5 & 11 (1 cms difference in the ipap from one end of the cpap hose to the other & 0.5 difference in the epap from one end of the hose to the other).

This was a big surprise & I will now try several other masks to see if this is common. Am not sure of the significance of this at the moment so will do more tests (it leaves me wondering about the accuracy of the CMS data in Encore Pro for this machine - if there is a 1 CMS loss & it is consistent across masks then the data recorded will be inaccurate). I'll try some different CMS settings as well.

##2 - Just tried same tests with VPAP III S/T & it too has the loss of 1 CMS from the machine to the mask !. So AutoScan too must be recording incorrect ipap values as the data that gets recorded in any of these machines, come gfrom what the machine thinks vs the reality measured by the pressure dial guage.

Using a nasal mask with the Bipap Auto seems to work ok for me at this stage (UMFF does seem to cause early epap/ipap flipping as is the case with the Bipap Pro 2 and S/T I have. But on this Autp Bipap even with the UMFF, when the gap is only 2 CMS it is so small it is not a problem). But with the data from the dial guage. It seems the gap is only 1.0 CMS and not the 2.0 CMS the machine claims.

On my PB330, because it has a seperate pressure sensing tube inside the main tube, the CMS readouts are the same at either end of the cpap hose.
10 /13 on the machine & exactly that on the dial guage at each end of the hose.

One other test was to try a Hybrid mask - the test failed but the mask seems to have a lot of promise. The problem I experienced was air blowing out from the top part of the mask when on my BP330 with epap/ipap set at 10/13. Epap seems to be ok but when Ipap cuts in the mask pulses then air seems to come out from near the nose prongs. This pulsing of the mask is a problem. It could be just a case of better assembly of the mask. I do like the way it will work as a nasal mask or full face mask depending on how you want to breathe. This seems a great idea. There does seem to be a lot of noise from the air vents (I may tape 1 or to of them up as a temp experiment).

DSM

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, bipap, hose, Encore Pro, CPAP, auto

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dsm wrote:I put a CMS dial guage on the machine & set it for
epap min 10
ipap max 14
ps 3
risetime 2
Using a Resmed Axctiva Nasal Mask (the floating one).

snip

What the Bipap Auto does is start off delivering the min epap and adjusts ipap to 2 CMS above this. So The readout on the machine showed 10 & 12 - when the dial guage was connected at the machine end of the hose, it also showed pressures of 10 & 12.

snip

Using a nasal mask with the Bipap Auto seems to work ok for me at this stage (UMFF does seem to cause early epep/ipap flipping

Hi DSM,

I have no idea what you are writing about but it seems to be very important so I am rereading and rerereading it!

A few questions, when you set up the pressure at 3, why not 4? I thought it was supposed to be the difference between the I and E.

What is rise time? Is that the same as BiFlex?

What is a CMS dial guage and before that, what is CMS?

Finally, what is epap/ipap flipping? I think I know what that is, as something happens initially with the machine where I feel like my breathing is out of synchronization. It's almost like someone who can't dance being on the dance floor.

I think, but I may be wrong, if when you did your titration, the pressures were off at the mask point as opposed to where it exits the machine and you are using the same equipment for your OSA therapy, it doesn't matter. However, an adjust needs to be made if other equipment doesn't have that pressure loss.

Very interesting post!

Allen

Allen,
I have added 2 lots of new material - all lines starting with ### are new
DSM

allend wrote:

dsm wrote:I put a CMS dial guage on the machine & set it for
epap min 10
ipap max 14
ps 3
risetime 2
Using a Resmed Activa Nasal Mask (the floating one).

### CMS is shorthand for 'CMS of Water (centimeters of water)' - that
### is the way the air pressure is measured that eminates from a cpap
### machine

### A CMS Dial guage is a fairly accurate guage for meassuring the
### pressure at the point in the air host that the pressure is sampled
### (the guage is show in use here
### http://www.internetage.com/cpapinfo/bipap-st-1 ) in photo 8 you
### can see it connected to the machine end of the airhose
###

### ps is the maximum pressure seperation the machine is to allow
### between ipap pressure (breathing in) and epap pressure (breathing
### out) when it starts adjusting the pressures in the night. The Auto
### Bipap monitors the breath-out & breath-in seperately & adjust them
### seperately but will always make sure they are adjusted such that
### the ipap never gets more than (ps + current epap). Put another
### way :- current ipap pressure (at any time in the night), minus the
### ps number, is the highest the epap pressure will be allowed to
### adjust to.
### (yes it is confusing, I only worked it all out once I got one of them).

snip

What the Bipap Auto does is start off delivering the min epap and adjusts ipap to 2 CMS above this. So The readout on the machine showed 10 & 12 - when the dial guage was connected at the machine end of the hose, it also showed pressures of 10 & 12.

### If the Bipap Auto is set with minimum epap at say 5 and maximum
### ipap at say 15 & ps set at say 4, this means that when the machine
### is 1st switched on, the epap (breathout) pressure will be 5, the ipap
### (breathin) pressure will get set to epap+2 = 7. If the machine
### detects breathingin (ipap) problems and increases ipap from the
### initial 7 to say 10 (an increas of 3 CMS), the epap setting will then
### also get increased so the max ps gap of 4 is maintained. Restated:
### ipap now 10, ps = 4 thus 10 - 4 = 6, so epap gets lifted to 6. If ipap
### caused further problems & got lifted to say 11 then epap would also
### get lifted by 1 to maintain the max ps gap of 4.

snip

Using a nasal mask with the Bipap Auto seems to work ok for me at this stage (UMFF does seem to cause early epep/ipap flipping

### My appologies, I tend to call the change from ipap to epap & epap
### to ipap 'flipping' as in the pressure 'flips' from one level to the
### other in the initial set up using the above example the initial epap
### of 5 'flips' to ipap of 7 & then on end of inhale 'flips' back to epap
### of 5 etc: flipping is probably not the best way to describe that
### process.
###
### Re: rise time, this is a setting that adjusts how fast the ipap flips
### to epap pressure or how fast the epap pressure flips to ipap.
### Changing the rise time is a comfort setting for the user. If the flips
### are too fast, some people dislike it. But the longer the rise time,
### the less air the user is getting and that is a consideration when an
### RT decides what risetime to recommend. Peopls with COPD or
### unique respiratory disorders should never really play with the
### risetime without RT awareness & preferably advice.

Hi DSM,

I have no idea what you are writing about but it seems to be very important so I am rereading and rerereading it!

A few questions, when you set up the pressure at 3, why not 4? I thought it was supposed to be the difference between the I and E.

### As added above, the ps setting is the maximum gap the machine
### will allow between ipap & epap as it automatically adjusts either epap
### or ipapa during the night.

What is rise time? Is that the same as BiFlex?
### Risetime is how quickly the machine will transition between ipap & epap

What is a CMS dial guage and before that, what is CMS?
### CMS dial guage (sold by cpap.com) is a dial guage for measuring the
### pressure coming from the machine (cms being centimeters of water).
### (see link added above)

Finally, what is epap/ipap flipping? I think I know what that is, as something happens initially with the machine where I feel like my breathing is out of synchronization. It's almost like someone who can't dance being on the dance floor.
### I have a somewhat restricted airflow through my nose compared to
### most people & thus tend to take slower longer breaths if nasal
### breathing. I have noticed that all models of Bipap that have 'AutoTrak'
### & when I nasal breath, tend to switch from ipap to epap before I have
### finished breathing & this gets to be a problem.


I think, but I may be wrong, if when you did your titration, the pressures were off at the mask point as opposed to where it exits the machine and you are using the same equipment for your OSA therapy, it doesn't matter. However, an adjust needs to be made if other equipment doesn't have that pressure loss.
### I must confess that I don't know what type of machines they use at
### RNSH where I did my study (am scheduled for a new one at end Feb).
### What my little test did was to indicate that there appears to be a 1 CMS
### pressure difference from the machine to the mask & that those
### machines that have seperate air pressure sensor lines, don't show this
### 1 CMS loss because they are accurately sensing the real pressure at
### the mask.
###
### At 1st I wondered if the lost 1 cms was due to the type of air hose but
### I tried 3 brands of hose & got 100% same result.
### Puritan Bennett machines have this seperate pressure air line, it runs
### inside the main airhose & is used to accuratey sample the pressure
### at the mask. The new Resmed Vpap Adapt also does this.
###
### The test I did shows that when the machine thinks there is say 12 CMS
### pressure at the mask & records this in the nightly data, in fact the CMS
### (according to the accurate dial-guage) is 1 CMS less than wat the
### machine thinks.
###
### What does this mean ? - only that the data recorded is inaccurate &
### thus misleading but not such a big deal that it is a serious problem.
###
### Anyone with a dial guage should be able to repeat my test easily.
### DSM

Very interesting post!

Allen

###### I have created a new thread on how the Bipap Auto works
viewtopic/t17136/How-the-Bipap-Auto-works.html